Ozone Resistance of Vulcanizates Based on XNB Rubber

The paper represents ozone resistance of rubbers based on carboxylated nitrile butadiene rubber cured with epoxy resins and magnesium oxide. Ozone resistance was investigated using the express-method at a flow rate of the ozone-air mixture of 9 l/h and ozone content of 9 mg/l. In the method used, the “time to cracking start” indicator was taken as the basic indicator of ozone resistance. The second indicator characterizing the ozone resistance of elastomeric materials was the "rate of destruction" in the main period of destruction. There has been evaluated the effect of dissolved polyvinyl chloride in epoxy resin ED-20 on the properties of vulcanizates. There has been investigated the Increase in destruction time under the action of ozone.

Studies of the Sulfonated Hydrogenated Styrene–Isoprene–Styrene Block Copolymer and Its Surface Properties, Cytotoxicity, and Platelet-Contacting Characteristics

Styrenic thermoplastic elastomers (TPEs) consist of styrenic blocks. They are connected with other soft segments by a covalent linkage and are widely used in human life. However, in biomedical applications, TPEs need to be chemically hydrogenated in advance to enhance their properties such as strong UV/ozone resistance and thermal-oxidative stability. In this study, films composed of sulfonated hydrogenated TPEs were evaluated. Hydrogenated tert-butyl styrene–styrene–isoprene block copolymers were synthesized and selectively sulfonated to different degrees by reaction with acetyl sulfate. By controlling the ratio of the hydrogenated tert-butyl styrene–styrene–isoprene block copolymer and acetyl sulfate, sulfonated films were optimized to demonstrate sufficient mechanical integrity in water as well as good biocompatibility. The thermal plastic sulfonated films were found to be free of cytotoxicity and platelet-compatible and could be potential candidates in biomedical film applications such as wound dressings.

STUDYING OF EFFICIENT AND SEMI-EFFICIENT CURING SYSTEMS INFLUENCE ON DYNAMICAL PROPERTY AND OZONRESISTANT OF RUBBER

There was showed dependence of the storage modulus and the loss modulus on shear deformation in torsion. For the first time type of curing system influence on Payne and Mullins effect is investigated. The Cole-Cole plots exhibit the contribution of the cross-linking system effect in the dynamic properties of rubber. There was increase of ozone resistance of rubber based on efficient curing system in condition general stress to critical stress is showed.

Development of Frost-Resistant Rubber Based on Epichlorohydrin Rubber of Hydrin T6000 Brand

The results of development of frost-resistant rubber based on epichlorohydrin rubber (ECHR) of Hydrin T6000 brand of Zeon Chemicals L.P. (USA) are described in the present work. The properties of ECHRs are determined by the nature of the structural units that constitute the macromolecules. The absence of olefinic functionality in the main chain gives ECHR the resistance to heat, oxygen, ozone and other factors. The presence of chlorine causes the high resistance of Hydrin T6000 rubber to the effect of hydrocarbon media (oils, fuels, fats, waxes, solvents), and the presence of oxygen atoms helps to maintain the flexibility and elasticity of materials at low temperatures. Hydrin T6000 rubber has the lowest glass transition temperature (Tgt= -60 ° C) from all the epichlorohydrin rubber brands, high oil resistance, increased heat and ozone resistance, and, therefore, attracts researchers' interest as a promising rubber for the development of frost-resistant rubber with sealing capability. The paper presents the formulation of rubbers based on Hydrin T6000 and the results of studies of their physical and mechanical properties. Analysis of the data revealed that the obtained rubber has excellent frost resistance, increased oil resistance at a satisfactory level of residual deformation after compression and strength characteristics. Thus, Hydrin T6000 has established itself as a promising rubber for manufacturing frost-resistant rubber with sealing function and will provide increased reliability and durability of equipment operation in extreme conditions of cold climate in Russia.

Characteristics of Vulcanizate Rubber Using Composite Latex – Modified Cassava Starch as Filler

The research on Characteristic of vulcanizate rubber using cassava starch composite (Manihot glaziovii) modification - latex as filler has been done. The composite variation of cassava starch concentration is 0, 40, 80, 120, 160 and 200 phr in three replications. Microstructure and elemental samples in SEM EDX and FTIR Spectroscopy method analysis, while physical properties using the standard testing equipment. The results showed that the concentration of cassava has a significant influence that is hardness, tensile strength, elongation at break, tear resistance and ozone resistance. The best rubber hardness specification was composite with modified cassava starch concentrations of 120, 160 and 200 phr with value 57, 61 and 65 Shore A. The best tensile strength of cassava starch concentration 80 and 120 phr with value 160 and 167 kg/cm2, while the best result of the extension of cassava starch concentration elongation at break 80, 120, and 160 phr is 652, 741, and 748%, and tear resistance 80, 120, 160 and 200 phr with value 14.21, 15.96, 15.16 and 14.47. The ozone resistance for all concentrations meets the requirements of commercial vulcanizate rubber. The latex-modified cassava starch composite can be used as a filler for rubber products and as an alternative to commercial fillers.